1. Field of the Invention
The invention relates to a light used for illumination, such as a headlight, a fog light, a signal light, traffic lights, spot lights, and other lights. In more detail, the invention relates to a light for this type of illumination that has a simple configuration with a reduced number of parts and good performance characteristics.
2. Description of the Related Art
FIG. 1 shows an example of a projector type configuration for a vehicle light 90 (see, for example, Japanese Patent Laid-Open Publication No. 2001-23419 and U.S. Pat. No. 6,416,210, the disclosures of which are hereby incorporated in their entireties by reference). The vehicle light 90 includes an ellipse group reflector 91 such as a revolved ellipsoid, a light source 92, a projection lens 93, and a light shielding plate 94. The light source 92 is arranged to coincide with the first focus f1 of the ellipse group reflector 91. Therefore, light emitted from the light source 92 is converged at the second focus f2 after reflecting on the ellipse group reflector 91.
At this time, the light reflected on the lower half of the ellipse group reflector 91 enters the projection lens 93 as light having an upward facing directionality after converging at the second focus f2. When the light emits from the projection lens 93, there is also a possibility that it might include an upward facing light component which may annoy opposing vehicles.
Consequently, the light shielding plate 94, that extends to the major axis X from the lower portion of the light 90, is provided close to the second focus f2 so as to block the light reflected on the lower half of the ellipse group reflector 91. This allows only the downward facing light reflected on the lower half of the ellipse group reflector 91 to enter the projection lens 93 and, in principle, prevents upward facing light from occurring.
For the case described above, if there is absolutely no upward facing light included, it will be difficult to read road side signs such as traffic signs when they pass on the left (or right) side, for example, when driving in a country that requires traffic to proceed on a left (or right) portion of the roadway. Because of this, a process is performed on the light shielding plate 94 so as to project a moderate amount of upward facing light to the left (or right) side to make it easier to read traffic signs and verify the presence of pedestrians.
However, the conventional vehicle light 90 comprises a light source 92 arranged along the illumination direction, a lengthwise ellipse group reflector 91, a light shielding plate 94 placed near the second focus of the ellipse group reflector 91, and a projection lens 93 that has a focus near the position of the light shielding plate 94, and is assembled with all components in the lengthwise direction. Thus, the vehicle light 90 generally requires a depth of approximately 170 mm to be installed. In addition, if the necessary space for replacing the light source 92 is considered, at least 200 mm or more are required. For example, in the conventional vehicle light 90, there is a problem in which the required space inside the engine compartment increases, which influences the design of the vehicle.